Modern Sustainable Roofing
The big challenge for roofing manufacturers is creating new roofing products that check all the sustainability boxes while maintaining or improving existing performance. Through all the environmental and sustainability challenges that we face in the building industry, we can’t lose sight of the ultimate goal: designing and implementing products and systems that provide the maximum sustainability benefits while maintaining or improving performance. It means considering the life cycle of the products within the design, their impact on the other products being used, the environmental benefits and the resiliency of the system. When it comes to low-slope roofing, there is no better roofing option that checks all the sustainability boxes than a green roof.
Green roofs are defined as a vegetated green space on top of a man-made structure installed above, below or at grade. In Australia, the green roofing market has continued to grow over the last 20 years due to their many recognized environmental, social and economic benefits. The benefits of green roofs have been so well recognized that many cities and councils throughout Australia promote the use of green roofs.
Out of all the green roof benefits, the main driving factor for many of the green roof mandates and incentive programs is their ability to retain and detain storm water. This is especially beneficial in cities, where there is often a lack of natural green space, instead being covered by manmade structures and materials. During heavy rainfall events, which have increased in frequency across Eastern Australia in recent years, storm water runoff from solid surfaces such as roofs can overrun a city’s storm water system. This can lead to flooding, overworked wastewater treatment facilities and an overrun of sewer systems resulting in the release of untreated water into local rivers and streams.
Green roofs act like a sponge on top of the roof, combining multiple products such as moisture retention mats, engineered growth media and vegetation designed to retain as much water as possible. Nonetheless, during heavy rainfall events, even the most well-designed green roofs can be overrun with water and runoff will occur. However, this runoff will be delayed, likely occurring after peak runoff from the other surrounding impervious surfaces. This delayed runoff is a result of a green roofs ability to retain and detain water.
By design, green roofs are covered in vegetation to make use of the absorbed storm water and to provide aesthetics. Naturally, like all other vegetation, green roof plants help to sequester carbon dioxide while at the same time producing oxygen. This is obviously very important everywhere but is especially important in cities where there is dense human population producing CO2 and little natural vegetation to offset it. The use of vegetation on green roofs helps to increase biodiversity, providing habitats for bees as well as other beneficial insects and wildlife such as birds, butterflies, beetles and fungi.